It is old and well known as evidenced by the patent to Little, U.S. Pat. No. 3,387,686 construct a collapsible wheel chock from heavy metal elements including a base frame and an upper frame hinged together permanently at one end thereof for movement of the upper frame from the position nested in the base frame to an upwardly inclined working position. Such a collapsible wheel chock is also provided with a support plate which will be disposed between the frames when nested and arranged to automatically assume a stand position therebetween when the upper frame is moved to the inclined working position. The support plate is also permanently pivoted to the upper frame and the upper frame and base frame are provided with an expanded metal anti-skid surface. Thus, the entire assembly is very heavy and cannot be disassembled for the replacement of a defective member.
It is also old and well known to construct a rigid, non-collapsible wheel chock from plastics material as evidenced by by Japanese Utility Model No. 5694/1967.